The embedding of a foreign body inside a cake of soap presents the problem of healing the defect or cut where the foreign body was inserted into the cake. This applies both to soap that is hand made and to soap made on automatic soap machinery.
Quality soap bars are extruded by an extruder press under high pressure, although the extruded billet of soap is somewhat soft and workable, as to shape, it is of a nature that if a cut or hole is made in the surface and body, this cut cannot be healed by pressing the cut surfaces together.
To try to embed a foreign in soap while it is being made on a high production automatic soap making machine presents not only the problem of the insertion cut or defect, but also the problem of not reducing the number of cakes produced per unit of time, the problem of not reducing the quality or smoothness of finish on the soap cakes, the problem of not increasing the cost of producing the soap as well as other problems.
In the case of inserting a flat plate having a central hole like a washer, yet additional problems present themselves. For example, how is the soft soap material handled to avoid gumming up the many things that touch it; how is the plate controlled to end up centrally located in the soap; controlled to end up flat in a plane parallel with the flat sides of the soap; controlled to end up with its hole concentric with the hole in the soap, controlled to end up solidly embedded in a rigid fashion so as to stay in position during the life of the soap cake, etc.
The following invention is a method to solve the problems presented when attempting to manufacture soap like my copending application Ser. No. 651,515. There is first a problem of sealing the defect made in a cake of soap when a soap plate is inserted into the body of a cake of soap. Such a defect does not heal by pressing it back together, even if moisture is also applied to the surfaces before they are pressed back together. It is not desirable to manufacture soap which cracks open due to moisture changes and which cracks make the soap look bad by the dirt such cracks collect and hold.